Baby behavior is quite the dichotomy. If there's nothing more annoying than a baby crying, there's nothing that'll make you smile quicker than a baby laughing his noggin off. Something about a baby's cuteness combined with high-pitched laughter and innocence makes a baby's giggling infectious. It doesn't hurt that amusing them takes so little effort, making their laughter one of the most adorable sights in the world.

Of all the tittering babies on YouTube, these are some of the cutest. Go ahead and bookmark the article. Whenever you're having a bad day, just hit the link and watch a few of these videos. You'll be back in good spirits in a flash.

Baby laughing hysterically at ripping paper

When's the last time you laughed when someone ripped paper over and over? Ah, to be amused by the simple things in life again...

Baby laughs so hard he cries

This little guy is in such stitches that he actually starts crying a little bit. Still, you can't help but have a grin play across your face.

Baby girl laughing hysterically at dog eating popcorn

Watching a dog stuff its face with popcorn is somewhat entertaining in its own right ... but this rug rat thinks it's the funniest thing since "Seinfeld."

Belly laugh

Even when a little chubster like this laughs but not rip-roaringly so, it's still endearing. Especially since he keeps squeaking all the while.

What's so funny?

Whenever a baby just laughs for no apparent reason, you've got to wonder what he thinks is so funny. Of course, after you get over laughing with him.

Laughing twins

What's better than one baby cracking up? A pair of them doing it in synchronized unison.

Quadruplets laughing

And what's better than twins laughing at the same time? How about four of them?